Electromagnetic clutch



May 28, 1946.

w. P. LEAR 2,401,003

ELECTROMAGNETIG CLUTCH Filed June 1S, 1943 ATTORNEY ""ing." In'thedrawing': v

Patented-MUZ@ 1946` i g UNITED STAT as PATENT `OFFICE t `amic'ritoMAcmuixrrc CLUTCH William P. Lear, Pidua,

Ohio, asslgnor, by mesne assignments," to Lear,

y ltapids, Mich., a corporation of Illinois f 1 Application June 1s, 1943, serial No. 96,974

- `s clanes. (c1. 19a-1s) This invention relates to clutches, and more particularly toanlimproved electromagnetic nonslip clutch.

As' a result-of ftestlinvestigations, it has been found that the slippage between the driving and "driven membersv of a clutch bears'a direct relation? to" the relative fconcentricity lof these 'members. If the members are so mounted thatfthev, are concentric inail positions ofrelative displacef ment, the slippage between the'driving anddriven members, whenengaged is reduced to substantially zero; LThis "results in increased eiliciency `mechanism such asiiexible shafting I3.

Incorporated, Grand housing Il, pinion I8. is connected to a driving The gearingconnecting pinion I3 to shafting I8 may be any conventional design adapted to produce the desired gear ratio. 0

Clutch housing` Il is `secured `to theend bell 2| of motor I0 inrany suitable manner, and encloses l the respective parts of the electromagnetic clutch.

Gear housing `2Iiis secured to housing I1. Armatureshaftll is mounted in a suitable bearing 22 secured in a recess 23 in a. substantially cylindrical `housing member24. Shaft II extends and reduced wear-of the clutching surfaces. The ,l

present invention isv an improvement ofthe clutch disclosed in my U. S. Patent No. 2,267,114.

It is 4therefore among theobjects of this invention to `provide an improved electromagnetic. clutch" construction in which the driving and ldriven members" are maintained in a concentric relation in all positions of relative displacement;

tto provide anfimpr'oved"electromagnetic `clutch having a' driving-member and a drivenmember "supported on acommonbearingsupport concen- 0 tricwitlfi both "'inembers; land to provide an improvedjelectromagnetic clutch in which there is substantially no slippage between the driving and vdriven members when'the clutch is energized@ *"Ifhese and "other objects', advantages andreaiturs' following description and accompanying i drawof the invention will be apparent from 4the Figi 1 iis an elevation view illustrating l'afmodied construction.

ffgFi'ggf 3ds a' cross-sectional view on the line 3-3 Hofr'igl.

Figgi 'is a erqssfsetionaiview on the liner--i According tothe present invention, continuous vconcentricii'ly of' the clutch surfaces in all posi- -t'ions is attained by" mounting both members on a common bearing/surface.` "For instance, both membersmay `haine av bearing surface on the armature orf'cirivev shaft ofan electric motor with which theclutch is associated. Referring to Fig.

"l, arr electric motor III islillustrat'ed having'an "armatureior'drive shaft I to which is connected "theildrivng member I2` of an electromagnetic clutch I5.` `'Driven member I3 of the electromagnetic clutch lhas afdrive 'shaft4 I4 secured thereto,

and the outer end of shaft I4 is formedas a drive pinion I6. Through suitable gearing contained in a gear housing secured to clutch through and beyondmembcr 24, and its reduced outer portion-4 0 is mounted on a bearing 4I in driveny member I3 in a. manner described hereinafter. An `energizing winding for producing the `magnetic aux for dutch l5 to estabnsn frictional engagement of members I2 and I3 is `mounted within member 24. Member 24 is made of suitable magnetic material, such as soft iron. To form part of member 24 and `complete the magnetic flux circuit, an annular inner shell member 26 ismounted in housing I1 surrounding coil 25 and extending outwardly therebeyond to a point between clutch `members I2 and I3.

Clutch member I2 comprises a hub portion 21, secured on shaft Il `by a key 28, and a disk-like clutching surface 30. lDriving member I 2 is made of suitablemagnetic material, such as soft iron.

30 To increase the magnetic attraction and number partly in section, of ifa mptrdri've system embodying the improved f'electromagnetic"clutch of the present invention. 1Fig'."2` is aisectional viewof a portion of FigI 1 of iux interlinkages between members I2 and I3,

Y an annularring `3l of non-magnetic material is 0 inserted in the disk portion 30. This construction is illustrated more clearly in Fig. 3'. The construction of the member I2 may be the same 'as `any one of the several driving members illustrated in my Patent No. 2,267,114, issued December23, 1941. `Such constructions, as explained in said patent, are to secure increased iiux interlinkage between the driving and driven members Y0f the clutch.` :This is accomplished by forcing the magnetic flux to pass back and forth between the driving and driven members one or more times.

- Driven member I3 comprises a disk portion or clutch surface 32. An annular braking surface 38 is mounted in recess 38. Recess, is of sufcient depth to permit member I3 to move away the necessary amount from member I2, when the clutch is deenergized, to have the braking surface on disk member 32 engage brake surface 38.

As has been stated, amature shaft II extends outwardly beyond member I2, and the outer reduced end 40 of shaft II is mounted in a bearing 4I secured in the outer end of extension 33. A coil spring 42 engages at one end the inner race 43 of bearing 4I and at the other end a spring seating washer 44 engaging an annular shoulder 45 on driven member I2. Spring 42 normally urges members I2 and I3 apart, and member I3 into engagement with brake surface 38. It will be noted that the spring extends between two surfaces which have no relative rotation. The relationship of brake surface 38, extension 33, reduced extension 40 of shaft I I, bearing 4I and spring 42 is shown more clearly in Fig. 4.

Member I2 is mounted on shaft II, and member I3 is mounted on bearing 4I, which in turn is mounted on end 40 of shaft II. Thisinsures a concentricity of the clutch surfaces 30 and 32, as both clutch members are mounted on the same bearing surface. In operation, when winding 25 is energized, member I3 is rapidly pulled into frictional engagement with member I2 to form a driving connection between shaft II and pinion I6. The path of the magnetic ux is indicated by the arrews in Fig. 1. The flux passes from housing member 24 into hub 21 of member I2, and thence into disk surface 30. From surface 30, the flux passes to surface 32 of member I3, then back to surface 30, and thence to inner shell 26 completing thecircuit. Due to the increased number of ux interlinkages between the clutching surfaces 30 and 32 by reason of incorporating ring 3i of non-magnetic material in disk 30, the clutch engaging action is extremely rapid. As both members are mounted on the same bearing support, they move in parallel planes in coming into engagement, and concentricity is assured. It has been found in tests that the slippage between members I2 and I3, when the clutch is energized, is substantially zero.

When winding 25 is deenergizei., spring 42 rapidly moves member I3 away from member I2 and into the position where surface 32 engages brake surface 38. Thus, motion of drive pinion I6 and driving mechanism I8 associated therewith is interrupted substantially instantaneously. The entire device, therefore, comprises a quick acting combined clutch and brake for connecting a motor to a drive system, and for stopping movement of the drive system when the motor is deenergized. Due to the quick action of the clutch, overrunning of clutch is substantially prevented. e

Fig. 2 illustrates a modied construction in which the bearings of member I3 in its housing and on the motor shaft are radially aligned. As shown, member I3 is formed with a cylindrical extension 43 which is shorter than extension 33. A housing is secured in housing I'I and has a recess I in which is mounted brake surface 38. A roller bearing assembly 52 is mounted on extension i8 and seated in another recess 53 in housing 50.

A roller bearing assembly 54 is disposed between motor shaft Il and extension 48. Bearing 54 is radially aligned with bearing 52. An and wall 55 on extension 48 maintains bearing yu in place. Extension la terminates in a drive /pinlon 58, which may be integral with the extension. In this construction, as in that of Figs, 1. 3 and 4. clutch members I2 and I3 are urged apart by a coil compression spring 51 extending between inner race 58 of bearing 54 and e washer 80 engaging a-shoulder 8| on hub 2l. The construction of Fig. 2 likewise has been found effective in insuring concentricity of the clutch surfaces in all positions, and thus reducing the slippage therebetween to substantially zero. v

While specific embodiments of the invention have been shown and described to illustrate how the principles of the invention may be applied,

- yit will be understood by those skilled in the are that the invention may be otherwise embodied without departing from the principles thereof.

What is claimed is:

l. An electromagnetic clutch comprising a driving shaft; a first member of magnetic material having a clutching surface, and keyed to and supported on said driving shaft; a, second mem-- ber of magnetic material having a clutching surface magnetically and frictionally coactable with the rst member surface and a tubular extension concentric with said driving shaft; a housing surrounding said second member; a-iirst bearing means between said tubularextension and said driving shaft; a second bearing means between said tubular extension and said housing, said bearing means being radially aligned on said extension; and magnetic flux generating means for producing magnetic flux for establishing frictional engagement between said clutching surfaces.

2. An electromagnetic clutch comprising. a, driving shaft; Ia. first member of magnetic material having a clutching surface and keyed to and supported on said driving shaft; a housing member of magnetic material surrounding said rst member and extending close thereto to establish a relatively low reluctance magnetic air gap therewith; a first bearing means between said housing member and said driving shaft; a second member of magnetic material having a clutching surface magnetically and frictionally coactable with the first member surface, a, braking surface and a tubular extension concentric with said driving shaft, said driving shaft having a reduced portion extending into said tubular extension; a second bearing means between said tubular extension and said reduced portion of said driving shaft; a housing surrounding said second member; a third bearing means between said tubular extension and said housing; a second braking surface on said housing adjacent the braking surface on said second member; resilient means normally urging said clutching surfaces apart and said braking surfaces into frictional engagement; and magnetic flux generating means including a winding supported within said housing member for producing magnetic flux for establishing frictional engagement between said clutching surfaces.

3. A clutch comprising a driving shaft; a driving disk keyed thereto; a, driven disk coactable with said driving disk and having a hub extension concentric with said shaft; a housing surrounding said driven disk; said driving shaft having a portion extending into said extension; a rst bearing between Said shaft portion and said extension; a second bearing between said extension and said housing; said bearings being radially aligned on said extension; resilient means biasing said disks apart; and means operative to drivingly engage said disks.

4. A clutch comprising a driving shaft; a driving disk keyed thereto; a driven disk coactable with said driving disk and having a hub extension concentric with said shaft; a housing surrounding said driven disk; said driving shaft having a portion extending into said extension; 9, housing member surrounding said driving disk; a first bearing between said housing member and shaft; a second bearing between said shaft portion and said extension; a. third bearing between said extension and said housing; resilient means biasing said disks apart; and means operative to drivingiy engage said disks.

5. A clutch' comprising a driving shaft; a driving disk keyed thereto; a driven disk coactable with said driving disk and having a hub extension concentric with said shaft; a housing surrounding said driven disk; said driving shaft having a portion extending into said extension; a braking surface on said housing adjacent said driven disk; a first bearing between said shaft portion and said extension; a. second bearing between said exten- `sion and said housing; said bearings being radial- 1y aligned on said extension; resilient means biasing said disks apart and said driven disk into engagement with said braking surface; and means operative to drivingiy engage said disks.

6. A clutch comprising a driving sh'aft; a driving disk keyed thereto; a driven disk coactable with said driving disk and having a hub extension concentric with said shaft; a. housing surrounding said driven disk; said driving shaft having a portion extending into said extension; a housing member surrounding said driving disk; a braking surface on said housing adjacent said driven disk; a first bearing between said housing member and shaft; a second bearing between said shaIt portion and said extension: a third bearing between said extension and said housing; resilient means biasing said disks apart and said driven disk into engagement with said braking surface; and means operative to drivingly engage said disks.

WILLIAMRLEAR. 

